The goal of this research study is to learn more about the clinical eficacy, or benefit, of Serostim (the Serono brand name for mammalian cell-derived human growth hormone) in the treatment of wasting associated with AIDS. Prior studies comparing Serostim with placebo (an inactive look-alike substance) have shown that Serotism is useful in increasing lean body mass (body tissue that is not bone or fat) and physical function. In this study, the clinical efficacy of Serotism will be based on change in exercise function after a specified course of treatment. An additional aim of this study is to determine the optimal, or best, dose of Serotism for the treatment of the HIV-associated wasting on change in lean body mass.